Method of grinding clutches, gears, and other toothed parts



June 4, 1946. V E. WILDIHABER 2,401,445

v METHOD OF GRINDING GLUTCHES, GEARS, AND OTHER TOOTHEDPARTS Filed March31, 1944 2 SheetS-Sheet 1 I Smaentor 8B fi zmas'r ,WILDHABHL I homeg-June 4, 1946. E. WILDHABER 2,401,446

METHOD OF GRINDING CLUTCHES, GEARS, AND OTHER TOOTHED PARTS Filed March31, 1944 tlzm'fisT Wu LDHABEIZ attorney 2 Sheets-Sheet 2 Patented June4, 1946' 2,401,446 METHOD OF GRINDING CLUTCHES, GEARS,

AND OTHER TOOTHED PARTS Ernest Wildhaber, Brighton, Gleason Works,Rochester,

of New York N. Y., assignor to N. Y.,.a corporation Application March31, 1944, Serial No. 528,885

The present invention relates to the grinding 11 Claims. (Cl. 51-287) ofthe tooth surfaces of face clutches; spiral bevel and hypoid gears, andof other toothed members, especially where the grinding surface and thesurface to be ground are counterparts of one another, as is the case incertain types of face clutches, and non-generated spiral bevel andhypoid gears.

In the grinding of face clutches, it is the usual practice to grind boththe sides and the bottoms of the tooth spaces. Ordinarily, a rotaryannular grinding wheel is employed, and grinding is effected by rotatingthe wheel in engagement with the work while producing a relative feedmovement between the wheel and work in the direction of the wheel axis.In such an operation, the rate of feed of the wheel is determined by therate at which stock can be removed from the bottom of a tooth space, andthe relative rates of feed in directions normal to the tip and sides ofthe wheel will, therefore, obviously be unequal, because the tip andsides of the wheel are diiferently inclined to the axis of the wheel.This causes unequal wear on the tip and sides of the wheel. Moreover,when the tooth spaces of the work have been previously cut, and thegrinding operation is used only to remove very slight amounts of stockfrom the sides and bottoms of the tooth spaces, the wheel will contactthe side of a tooth space long before it contacts the bottom of thetooth space, and, while the wheel may be fed into the work at a.relatively fast rate while it is grinding only a side of a toothsurface, the feed has to be slowed down prior to engaging the toothspace bottom. Sometimes the rate of feed in a direction normal to thetooth side is then so reduced that danger of burning the tooth sidearises through rubbing of the side of the wheel against the side of thetooth. These difliculties have all seriously hindered the development ofclutch-grinding.

In grinding non-generated spiral bevel and hypoid gears, the usualpractice is to grind both sides of a tooth space simultaneously, andfrequently the bottom of the tooth space is also ground in the sameoperation with the sides.

Here the difilculties arising from the differences in relative rates offeed on the sides and tip of the wheel have been recently aggravated bythe fact that it has lately become the practice to grind noneneratedspiral bevel and hypoid gears with wheels whose opposite sides haveunequal pressure angles so as to obtain more favorable tooth shapes onthe teeth of the mating pinion. The unequal pressure angles on the twosides of the wheel mean that the relative rates of feed of the wheel arenot only different between the tip and each side of the Wheel butbetween the two sides of the wheel themselves.

.A primary object of the present invention is to provide a method forgrinding clutches, gears and other members having formed tooth surfacesin which the rate of feed may be equalized on the sides and tip of thegrinding wheel.

. A further object of the invention is to provide a method for grindingparts, such as mentioned, in which, because of equalization of the ratesof feed and equalization of wheel-wear on the sides and tip of thewheel, the tooth surfaces may be round at a faster rate than heretoforewithout danger of burning.

Other objects of the invention will be apparent hereinafter from thespecification and, from the recital of the appended claims.

In grinding a clutch or gear or other part according to the presentinvention, the wheel i fed relative to the work in a direction normal tothe two sides of the work which are engaged by the wheel. In the case ofclutches, this means that the feed employed is in a direction bisectingthe angle between the side and the bottom of the tooth space beingground, and in the case of non-generated gears, whose opposite toothsides are to be ground simultaneously, this means that the feed will bein a direction bisecting the angle between the two sides of the toothspace. There are two outstanding advantages obtained with the presentinvention. The'two sides, or the side and bottom, of a tooth space maybe engaged by the grinding wheel simultaneously, and the feed on thesides, or on the side and bottom, is balanced and can therefore be keptat a maximum on both sides or on both the side and bottom. Therefore,the feed motion is not limited, as in the past, by the maximum rate offeed possible on one side or on the tooth space bottom, but can proceedat top speed on both engaged surfaces, simultaneously.

Several difierent embodiments of the invention are illustrated in theaccompanying drawings, in which:

Fig. 1 is a sectional view in a plane perpendicular to the axis,illustrating diagrammatically the 7 method of grinding a clutch memberaccording to the present invention;

Fig. 2 is a fragmentary side elevation showing two face clutch membersmade according to this invention in engagement;

Fig. 3 is a part elevational, part sectional view along the line 3-3 ofFig, 1, further illustrating the principles of the invention as appliedto the: grinding of a. face clutch member, which has side tooth surfacesof positive pressure angle;

Fig. 4 is a fragmentary sectional view illustrating one method ofgrinding according to this invention a face clutch member having sidetooth surfaces of zero pressure angle;

Fig. 5 is a similar view illustrating one method of grinding the clutchmember which is to mate with the clutch member of Fig. 4;

Figs. 6 and 7 are a fragmentary plan view and a fragmentary sectionalview on the line 1-1 of Fig: 6. respectively, illustrating one method ofgrinding non-generated spiral bevel or hypoid gears according to thisinvention; and

Fig. 8 is a fragmentary plan view, illustrating diagrammatically thestructure of a grinding machine which may be employed to practice theinvention.

Fig. 2 shows a pair of mating clutch members l0 and II in engagement.The two clutch members may be of identical construction, or one may havelongitudinally convex tooth sides and the other longitudinally concavetooth sides as described in my copending application Serial No.

444,031, filed May 22, 1942, and which matured as Patent NO. 2,384,582,dated September 11, 1945.

or inclination to the axis I! of the clutch."

The present invention is herein specifically illustrated as applied tothe production of the clutch member "I whose opposite side toothsurfaces are of longitudinally convex shape, but it will be understoodthat the invention is equally applicable to the production of a clutchmember whose opposite tooth surfaces are both longitudinally concave, orone longitudinally convex and the other longitudinally concave. In fact,the invention may be applied to the grinding of the tooth, surfaces of aclutch member regardless of its lengthwise tooth shape.

- The clutch member 10 shown is made accordin to the principles of myprior application Serial No. 444,031 above mentioned and has the oppsite sides of spaced teeth formed as parts of a common surface ofrevolution. In the illustrated embodiment, they are parts of a commonconical surface. Thus, the side ISa of a tooth In of the clutch memberis a part of the same conical surface which contains the opposite sidellb of a spaced tooth i2b of the clutch member. This conical surface isdenoted in Fig. 1 by the line It. Its axis is at I] parallel to the axisll of the clutch member.

The two tooth sides "a and llb and all other pairs of tooth sides can beground simultaneously with the inside conical surface I! of a rotaryannular grinding wheel 20 whose inside surface'is of the same pressureangle as the side tooth surfaces l3 and I4 and whose axis 2| in fulldepth position coincides with theaxis I'l of the tooth surfaces. Theinside surface of the grinding wheel, in other words, is the counterpartof the side surfaces to be ground.

' is withdrawn from engagement with the work, and

the work is indexed. With such feed. the inside surface I! of the wheelcontacts the tooth si es grinding stock is left previously stated,

Each member has teeth I! whose opposite side surfaces l3 and H are ofpositive pressure angle 4 i3 and ll of the tooth spaces long before thetip surface 22 of the wheel contacts the tooth space bottom l8, assumingthat the same amount of I on the sides and bottoms of the tooth spaceswhich is the usual practice. with the previous method of grinding, then,the axial feed movement of the wheel may be at a relat vely fast rateduring the grinding of the sides of the teeth but has to be slowed downfor the grinding of the tooth-space bottoms. It is this reduction infeed rate that in some cases, as

, .causes the feed movement normal to the sides of the tooth spaces tobecome so small that danger of burning the sides arises through rubbing.

tion, in'at least the final stage of grinding, when the sides andbottoms of the tooth spaces are engaged bythe sidesand tip of the wheel,the feed movement is in a direction bisecting the engaged toothsurfaces. The grinding wheel may, however, during the first part of thereed movement. beadvanced at a relatively rapid rate along its axis 2|from a position such as denoted in dotted lines at 20 Fig. 3, where thewheel is disen aged from the work, to a position such as'denoted at 20",where it has entered into two spaced tooth spaces of the work but whereit is still out of grindingengagement with both the sides and thebottoms of the tooth spaces. The axial feed movement in fact ispreferably continued to a point where the separation between the wheelsur- Heretofore a clutch of the character shown has only in its finalstage II, has, of course,

' space. In other words,

all of the tooth sides have face and the work is at a practical minimum,and sometimes in the final stages of this axial feed movement, theactive side surface of the wheel will then actually come into grindingengagement with the high teeth of the work. When this position isreached, the direction of the feed movement is changed in the method ofthe present invention, and the wheel is then fed, as already described,in a direction 2! which is inclined to the wheel axis 2| and whichapproximately bisects the angle between the side surface of a toothspace being ground and the bottom of thattooth in the final stage of thefeed movement, the wheel is fed from position 20" to the full lineposition 20.

Mathematically, the side profiles of the tooth surfaces being conicalwould appear as curved lines in the section of Fig.3. They are, however,herein shown straight for the purposes of illustration. The shownstraight lines can be considered as the mean tangents to the toothsurfaces.

In practicing the present invention, one pair ground for their samelimited depth, the wheel may be fed fur-- ther into the work and asecond grind at a further limited depth taken on all the teeth, and thisoperation may be continued until the wheel has been fed in direction IIinto full depth and depth. In either method, the feed erably in thedirection of the wheel axis and in a direction inclined thereto andbisecting the angle between the side and the bottom surfaces to beground.

An'annular grinding wheel, such as the wheel surface contact with thework. To avoid burning of the work surfaces, it may be desirable toimpart a series of rapid reciprocabeen ground to full is firstpl6fneonate tions to the wheel during the grinding operation accordingto the principles of the method disclosed in Ccndon Patent No. 1,979,876of November 6, 1984;. With this method, the feed from the position Bil"to the full line position is in the direction of the arrow 25 isperformed in an oscillatory manner, in other words, it is broken up intoa series-oi miniature strokes whereby grinding engagement time. Thispermits of maintaining a suitably fast grinding speed during actualgrinding contact even on a clutch member of large face width wherecontinuous contact between the wheel and the work would be too much forthe wheel to handle and wheres. mere reduction in the rate of feed mightcause burning.

Fig. 4 illustrates the a plication of the procceases part of the;

ess to the grinding of the sides and bottoms of v the tooth spaces of aclutch member liil whose tooth sides 88 and shore of zero pressureangle, that is, extend in the direction of the axis 35 of the clutchmember. Here an annular grinding wheel all? may be employed that has aninside active grinding surface 3Q which is. of. positive pressure angleand inclined to the axis til of the wheel, and that has a tip surface 32which is conical and inclined to the inside or" the wheel at such anangle as to produce tooth space bottoms in the worlr which areperpendicular to the tooth sides ill and 32 of the work. The wheel as ispositioned in engagement with the work so that the axis 655 oi. thewheel is inclined to the root surface oi the work at substantially thepressure angle of the active side surface oi the wheel. Here, as in thepreviously described embodiment oi the invention, the gnndiug wheel isfirst advanced axially and then the direction oi feed is changed tofollow the arrow 65 which bisects the angle between the side 35 or of atooth space and tom 33 of that tooth space. tion of the wheel is shownin dotted lines at 38 in the final position or its axial feed movementand in full lines at ts in the final position of its inclined feedmovement. Again opposite sides of spaced teeth oi the work may be groundsimultaneously to have longitudinally convex side surfaces which areparts of a common conical surface of revolution.

The tooth spaces of the clutch member so, which is to engage with clutchmember Bil, may

The active porbe ground with the outside conical surface so of a rotarygrinding wheel 6b whose axis $8 is in cllned to the root surface 53of'the work at substantially the pressure angle of the active sidesurface of the wheel. As before, the wheel may be advanced axially untilit approaches grinding contact, and then the direction of feed ischanged to follow the bisector 65 of the angle between a tooth side stor 52 oi the work and the tooth-space bottom til.

The invention is by no means limited to production of clutch members.Figs. 6 and '7 show how the principles of this invention maybe appliedto the production of spiral bevel and hypoid gears with grinding wheelswhose opposite sides have different pressure angles.

it denotes the gear which is to be ground. This gear has opposite sidetooth surfaces ll and i2 and rounded tooth space bottom surfaces 12. Forgrinding the gear, a rotary annular grinding wheel til is employed whoseinside. outside, and tip surfaces Si, 82, and 83, respectively, arecounterparts of the profiles of the side and bottom surfaces ll, 72, and13, respecthe bot- 6 tively, oi the tooth spaces of the gear, but,

whereas the side surfaces H and 12 of the gear are of equalpressureangle or inclination to the gear axis 15, the inside surface 8|of the wheel is of substantially greater pressure angle than the outsidesurface $2 of the wheel, being more inclined to the wheel axis 85.

When a wheel, such as the wheel 80, having un-' wheel into the work isin a. direction inclined to the wheel axis 85 and along a, line 83 whichsubstantially bisects the angle between the two sides i: and E2 ofthe-tooth space being {ground Two different positions of the wheelduringifeed are shown in full lines at 8% and in dotted lines at so,respectively. direction 86 until full depth position has been reachedand the tooth space" has been -fully ground. Then the wheel is withdrawnfrom engagement with the work and thework indexed tobring the wheel intoposition togrind a new tooth space. As before, the wheel may beoscillated back and forth during the feed movement to avoid burningaccording to the principles of the Camden patent above mentioned. Thetwo sides of the tooth space are surfaces of revolution.

Fig. 6 represents a view along the axis 35 of the sides of a tooth spaceof a gear. 88 is the gear apex and 7% denotes the gear axis projectedinto the plane of the drawing. 88 and flit, respectively, denote thepaths of points in opposite sides of the wheel during the grinding ofopposite sides 76 and it of a tooth space of the work.

The invention may be practiced on any suitable type of grinding machine.Fig. 8 is a frag mentary plan view illustrating diagrammatically thestructure of one such machine. is again clenotes the gear to be ground,is its axis, and it its apex. The grinding wheel 80 is secured to aspindle (not shown) which may be driven by a motor or any other suitablemeans. The spindle may be journaled in a sleeve (not shown) which ismovable in the direction of the axis 55 of the wheel to produce theaxial feel movement of the wheel. This movement may be efiected in knownmanner by a rotary cam. The sleeve is mounted on a slide 9b which isadjustable along the wheel axis so to permit of compensation for wear ofthe wheel. The slide is mounted on a swivel plate which is pivoted at 92on a Slid ing base 93, aguide way so being provided on the upper face ofthe sliding base 93 for this purpose, The pivotal adjustment of theplate @l permits or adjusting the axis of the grinding wheel at any'desiredangle to the. direction 98 of mo-- tioncf the sliding base to onthe bed 97 of the machine. Motion of the sliding base Q3 may becontrolled by'a cam or any other suitable means. The work-piece F8 ismounted in a 'worlrheacl which is adjustable on the angularly about'theapex le er the work, la er ally. axially, and" vertically, that is,parallel to the pivot axis l6. I i

In operation, the wheel is first moved axially by the cam on the sleeveto near grinding position and then is fed, by movement of the slidingbase Thewheel reed continues-in theground as coaxial conical.

bed of the machine tion about the work axis.

93, in the direction 86 which bisects thesides of the tooth space beingground. The latter feed may be continuous or be a reciprocatory feedmovement of the general type described in the Condon patent. Usually aplurality of cycles are performed in each tooth space of the work, thewheel being fed a limited distance during each cycle and then beingwithdrawn and the work indexed, the feed being preferably anintermittent feed movement taking place after a cycle of operation hasbeen performed on each tooth space of the work. v

The machine described with reference to Fig. 8 may be used for grindingclutches as well as gears. When a clutch is to be ground, the work is soset up that the direction 25 (Fig. 3), ll (Fig. 4) or I! (Fig. 5) ofgrinding feed proper coincides with the direction 98 of feed of thesliding base 93.

The invention can also be practiced, both in the grinding ofnon-generated gears and of clutches, on Gleason spiral bevel and hypoidgenerators of known construction which are provided with means fortilting the grinding wheel. this case, a feed movement in a directioninclined to the wheel axis may be performed in the normal plane, such asthe plane I! of Fig. 6 which contains the wheel axis It. Further thanthis, the feed in the direction inclined to the wheel axis may also beattained as the resultant of a plurality of feed motions. for instance,as a combination of feed along the wheel axis and feed angularly aboutthe work axis. In other words, the grinding feed proper may consist of afeed alon the wheel axis plus a simultaneous rotary mo- While theinvention has been described in connection with the grinding of gearsand clutches with an annular type of grinding wheel, it will beunderstood that it is also applicable where a cupped wheel is employed.It will further be understood that the invention is not limited to theproduction of clutches and of non-generated gears, but may be employedalso in the production of other parts where there are two surfaces to beground which are inclined at an angle to one another. It may thus beused, for instance, in the sharpening of blades of a milling cutterwhere the front face of a blade and the bottom of the space betweensuccessive blades have to be ground simultaneously. Again, the feed isin a direction bisecting the surfaces which are to be ground. In allcases, the surfaces ground are surfaces of revolution; such as conicalor spherical surfaces, or planes; and ordinarily surface contact betweenthe wheel and the work exists at least for an instant. In general it maybe said that while certain embodiments of the invention have beenillustrated. the invention is capable of further modification and thisapplication is intended to cover any variations, uses,'or adaptations ofthe invention following, in general, the principles of the inventionandincluding such departures from the present disclosure as come withinknown or customary practice in the art to. which the invention pertainsand as may be applied to the essential features hereinbei'ore set forthand as fall within the scope of the invention or the limits of theappended claims.

Having thus described my invention, what I claim is:

l. A method of simultaneously grinding a side and the bottom of a toothspace of a toothed member, which comprises employing arotary grindingwheel that has a side and a tip surface which are counterparts, in shapeand in inclination to one another, of the side and bottom of the toothspace to be ground, and rotating the wheel in engagement with the workwhile effecting a relative depthwise feed movement between the wheel'andwork in a direction other than at right angles to the wheel axis andapproximately bisecting the angle between the side and bottom of thetooth space.

2. A method of simultaneously grinding a side and the bottom of a toothspace of a toothed member, which comprises employing a rotary grindingwheel that has a side and a tip surface that are counterparts, in shapeand in inclination to one another, of the side and bottom of the toothspace to be ground, and rotating the wheel on its axis whil effecting arelative depthwise feed movement between the wheel and the work in adirection substantially normal to the bottom of the tooth space untilthe wheel and work are approximately in grinding contact, and theneffecting a relative depthwise feed movement between the wheel and thework in a direction other than at right angles to the wheel axis andapproximately bisecting the angle between the side and bottom of thetooth space until full depth position is reached.

3. A method of grinding simultaneously opposite sides and the bottoms oftwo spaced tooth spaces of a face clutch member which has side toothsurfaces of positive pressure angle, which comprises employing a rotaryannular grinding wheel that has sid and tip surfaces which arecounterparts, in shape and inclination to one another, of the sides andbottoms of the tooth spaces, positioning said wheel with its axisparallel to the axis of the work and so operate in two spaced toothzones of the work simultaneously, and rotating the wheel in engagementwith the work while effecting a relative depthwise feed movement betweenthe wheel and work in a direction inclined to both the axis of the wheeland the axis of the work and bisectlns the angle between a side and thebottom of a tooth space.

4. A method of simultaneously grinding a side and the bottom of a. toothspace of a toothed member which comprises employing a rotary annulargrinding wheel that has a side and tip surface which are counterparts,in shape and inclination to one another, of the side and bottom of thetooth space, and rotating the wheel on its axis while effecting arelative feed movement axially of the wheel until the wheel and work areapproximately in grinding contact. and then effecting a relative feedmovement in a direction inclined to the wheel axis and approximatelybisecting the angle between the side and bottom of the tooth space untilfull depth is reached.

5. A method of simultaneously grinding opposite sides of a tooth spaceof a toothed member whose opposite side tooth surfaces have differentpressure angles, which comprises employing a rotary annular grindingwheel which has opposite side surfaces that are counterparts. in shapeand inclination to one another, of the sides of the tooth space to beground, and rotating the wheel in engagement with the work whileeffecting a relative depthwise feed movement between the wheel and workin a direction inclined to the axes of the wheel and the work andbisecting the angle between the sides of the tooth space.

6. A method of simultaneously grinding opposite sides of a tooth spaceof a toothed member whose opposite side tooth surfaces have differentpressure angles, which comprises employing that it will a rotary annulargrinding wheel which has opposite side surfaces that are counterparts,in shape and inclination to one another, of the sides of the tooth spaceto be ground, and rotatin; the wheel on its axis while effecting arelative depthwise feed movement between the wheel and the work in thedirection of the axis of the wheel until the wheel and work areapproximately in grinding engagement, and then effecting a relativedepthwise feed movement between the wheel and work in a directionapproximately bisecting the angle between the sides of the tooth-space.

7. A method of simultaneously grinding on a toothed member two surfacesof a tooth space which are concentric surfaces of revolution andinclined to one another, which comprises rotating an annular grindingwheel on its axis while effecting a relative depthwise feed movementbetween the wheel and work axially of the wheel and thereafter effectinga relative depthwise feed movement between the wheel and work in adirection at. an angle to the wheel axis.

8. A method of simultaneously grinding two surfaces of a tooth spacewhich are inclined to one another, which comprises rotating a grindingwheel, which has active grinding surfaces that are counterparts of thesurfaces to be ground, on its axis while effecting a relative depthwisefeed movement between the wheel and work which is in one direction andat a relatively fast rate until the wheel and work are approximately ingrinding contact and which is in a direction inclined thereto and at arelatively slower rate until full depth position is reached.

9. A method of simultaneously grinding two surfaces of a tooth spacewhich are inclined to one another which comprises rotating a grindingwheel on its axis while effecting a relative depthwise feed movementbetween the wheel and angle to the first described feed movement andsubstantially bisecting the angle between the two surfaces which are tobe ground.

10. A method of grinding simultaneously opposite sides of a tooth spaceof a toothed member whose opposite side tooth surfaces have equalpressure angles or inclination to the axis of said member whichcomprises employing a rotary grinding wheel that has active side toothsurfaces at opposite sides of unequal inclination to its axis and thatin shape and inclination to one another are counter parts of the sidetooth surfaces to beground, and rotating the wheel in engagement withthe work while eifecting a relative feed movement between the wheel andwork in a direction inclined to the wheel axis and blsecting the anglebetween the opposite sides of the tooth space,

11. A method of grinding simultaneously a side and the bottom of a toothspace of a clutch member whose side tooth surfaces are of zero pressureangle and parallel to the axis of the clutch member which comprisesemploying a rotary grinding wheel-that has an active side surface ofpositive pressure angle and inclined to its axis and whose side and tipsurfaces, in shape and inclination to one another, are counter parts ofthe side and bottom of the tooth space to be ground, and rotating thewheel in engagement with the work, while effecting a relative feedmovement between the wheel and work in a di-- rection bisecting theangle between the side and bottom of the tooth space to be ground.

ERNEST WILDHABER.

